As a German who's spent a total of about half a year (maybe too little!) in the US, I think you've kind of nailed it with this explanation, but there's a part that's missing to me.
On the one hand, focusing on potential rather than flaws is exactly what feels like one of the things that could be better here. Also, as you say, there's nothing necessarily mendacious about a little bit of friendliness.
On the other hand, the thing that somewhat rubbed me the wrong way in the states wasn't ever the extraversion or friendliness / politeness in itself, but rather those situations where I felt like a particular positive (sometimes highly) emotional reaction was somehow socially expected in a professional context, and then watching people turn into actors to fill the role.
One example of this that I remember vividly was a session at a scientific conference, where a series of larger and smaller prizes were awarded. Some to just grad students, some to senior professors.
The laureates typically had to give a small speech. Everybody tried super hard to act and talk "honored", "humbled", "grateful". Most of them weren't great actors, and looked rather uncomfortable in the process. It was somewhat creepy to watch for me.
The part that was strange to me wasn't the fact that they were saying thanks (obviously), I guess that would be the same anywhere in the world, but rather how they all seemed to think it was necessary to play-act strong displays of emotions.
To me, that was the clearest example of this that I've seen so far, but in general it just seems like Americans have much less of a problem with professional social expectations creeping into the most private realm of your personality.
On the one hand, focusing on potential rather than flaws is exactly what feels like one of the things that could be better here. Also, as you say, there's nothing necessarily mendacious about a little bit of friendliness.
On the other hand, the thing that somewhat rubbed me the wrong way in the states wasn't ever the extraversion or friendliness / politeness in itself, but rather those situations where I felt like a particular positive (sometimes highly) emotional reaction was somehow socially expected in a professional context, and then watching people turn into actors to fill the role.
One example of this that I remember vividly was a session at a scientific conference, where a series of larger and smaller prizes were awarded. Some to just grad students, some to senior professors.
The laureates typically had to give a small speech. Everybody tried super hard to act and talk "honored", "humbled", "grateful". Most of them weren't great actors, and looked rather uncomfortable in the process. It was somewhat creepy to watch for me.
The part that was strange to me wasn't the fact that they were saying thanks (obviously), I guess that would be the same anywhere in the world, but rather how they all seemed to think it was necessary to play-act strong displays of emotions.
To me, that was the clearest example of this that I've seen so far, but in general it just seems like Americans have much less of a problem with professional social expectations creeping into the most private realm of your personality.